This web site was cyberjournalist.net and provides a comprehensive list of different blogging sites - what's new, what's been around the longest, etc.
I found an interesting link to information about one of the first blogs used to cover a major news event. It happened in 1998 with the coverage of Hurricane Bonnie for the Charlotte Observer by Jonathan Dube.
Dube and a team of journalists covering the hurricane update the web every half-hour and decided to post this information to get readers up-to-speed on new developments, which the newspaper couldn't do.
They proved that this form of blogging was journalistically sound, by editing the stories, etc., just as they would have for the paper. They made a breakthrough when deciding to use blogs as a journalistic medium instead of newsprint.
More information about this can be found at Poynter Online: http://www.poynter.org